awk: fix compat issue found by gpm build

function                                             old     new   delta
as_regex                                             105     131     +26
hash_find                                            247     233     -14
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 26/-14)             Total: 12 bytes

1 files changed, 5 insertions, 0 deletions

diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index 953a6e5e1..8e72dd38f 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -22,6 +22,11 @@ testing "awk hex const 1" "awk '{ print or(0xffffffff,1) }'" "4.29497e+09\n" ""
 testing "awk hex const 2" "awk '{ print or(0x80000000,1) }'" "2.14748e+09\n" "" "\n"
 testing "awk oct const"   "awk '{ print or(01234,1) }'"      "669\n"         "" "\n"
 
+# '@(samp|code|file)\{' is an invalid extended regex (unmatched '{'),
+# but gawk 3.1.5 does not bail out on it.
+testing "awk gsub falls back to non-extended-regex" \
+        "awk 'gsub(\"@(samp|code|file)\{\",\"\");'; echo \$?" "0\n" "" "Hi\n"
+
 tar xjf awk_t1.tar.bz2
 testing "awk 'gcc build bug'" \
         "awk -f awk_t1_opt-functions.awk -f awk_t1_opth-gen.awk <awk_t1_input | md5sum" \